Disc brake

ABSTRACT

A disc brake of the type in which friction pads or small friction surfaces are carried on opposite sides of the disc which rotates with a vehicle wheel or other rotatable part of the vehicle. The friction pads are spring urged into contact with the disc to retard or stop the vehicle and are normally held out of contact with the disc by fluid pressure.

United States Patent 1151 3,661,234

Moederndorfer et al. 1451 y 9, 1972 [54] DISC BRAKE 2,481,127 9/1949Ledwinka ..188/59 Inventors: Herbert Moederndorier; George E. Sch.3,465,850 9/1969 Sexton l 88/170 X both of Aurora, FOREIGN PATENTS ORAPPLICATIONS 1731 Assign?I Campilla' Peoria 1,017,561 1/1966 GreatBritain 188/1 71 [22] Filed: May 22, 1969 Primary Examiner-Duane A.Reger [211 PP 826,802 Almrney-Fryer, Tjensvold, Feix, Phillips & Lempio52 US. Cl ..l88/l70, 188/723 1 1 ABSTRACT [51] Int. Cl ..Fl6d 65/24 Adisc brake ofthe t I r ype 1n WlllCh frlctlon pads or small fncuon [58]new of Search 188/723 l rag 5 surfaces are carried on opposite sides ofthe disc which rotates with a vehicle wheel or other rotatable part ofthe vehicle. The friction pads are spring urged into contact with thedisc to re- [56] References Cited tard or stop the vehicle and arenormally held out of contact UNITED STATES PATENTS with the disc byfluid pressure.

2,382,552 8/1945 Eksergian et a1. ..188/59 4 Claims, 2 Drawing FiguresPATENTEUMAY 9 I972 SHEET 1 OF 2 INVENTORS HERBERT MOEDERNDORFER GEORGEE. SCHUBERT ATT RNEYS BY z w wz; a, 7

PATENTEDMAY 9 m2 3, 661 ,234

INVENTORS HERBERT MOEDERNDORFER GEORGE E. SCHUBERT W/WZ 7 +49 ATTORNEYSDISC BRAKE The conventional shoe and drum type parking and emergencybrake has several disadvantages, one being that of heat build-up duringbraking which causes brakes to fade. Another problem is that such brakesare generally mechanically actuated and applied manually by an operator.Generally, such brakes do not meet specifications of some states whichrequire a safety brake having the capacity to stop a fully loadedvehicle in emergency situations when the primary brakes have failed. Thepresent invention provides braking means which overcome the abovementioned disadvantages and provide a brake that is applied by springmeans and disengaged with fluid under pressure to overcome the springmeans; thus, giving an emergency type of operation. Another advantage isthat the brake has a self-centering feature which automatically causesapplication of braking pressure equally to opposite sides of the disc. Amore complete understanding of the mentioned will be had upon reading ofthe following specification wherein reference is made to theaccompanying drawings.

In the drawings:

FIG. 1 is a view in front elevation with parts in section of disc brakemechanism embodying the present invention; and

FIG. 2 is a view in side elevation of the same mechanism as viewed fromthe right side of FIG. 1 and with parts in section.

In the drawings, a brake disc is shown in both views and in FIG. 2, thedisc is shown as fixed to a shaft 12. This shaft may be any part of thedrive train of a vehicle such, for example, as the drive shaft betweenthe transmission and driven wheels or it may be a stub shaft projectingfrom the transmission itself. It is important that it be a shaft whichrotates with the wheels of the vehicle so that retarding the disc willretard the speed of the vehicle. Disc brakes of the kind generallyreferred to herein are also sometimes interconnected directly with thewheels including front wheels which, though not driving wheels, canserve for braking purposes. Briefly, it will suffice to understand thatmovement of the vehicle is accompanied by rotation of the disc 10 sothat braking of the disc will also apply braking force to the entirevehicle.

Braking is accomplished, as is conventional in disc type brakes, bypressing a pair of friction pads against opposite sides of the disc.Such pads are shown at 14 in FIG. 1 and each is mounted upon a metallicback 16 received in a recess 18, there being one for each of a pair oflevers 20. The friction pad assemblies are held within the recesses 18by dogs 22 and cap screws 23. These are also shown in FIG. 2 wherein thedogs are illustrated as received in recesses, one of such recesses beingshown at 24 in FIG. 1 where the dog 22 has been removed. This figurealso illustrates the pad as resting on a raised area 26 in the bottom ofrecess 16 which permits rocking of the pad so that its entire surfacewill readily come into frictional contact with the disc as it is movedtoward the disc.

The levers 20 are pivotally connected by pins 28 within a housing 30which housing is secured by cap screws 32 to a stationary part of thevehicle shown at 34 which might be a boss on a transmission housing orthe like. The housing 30 has a recess entering from one side, asrepresented in dotted lines in the drawings, for receiving a part of thedisc 10. Braking force is applied by a spring 36 in a cylindricalchamber 38. The spring bears against a wall 40 of the chamber and alsoagainst a piston 42 reciprocably mounted in the chamber. The piston hasa rod 44 extending outwardly through a wall 46 of the same chamber andslidable through a bushing 48 which is also shown in FIG. 2. A bolt 50extends through the piston rod and has a threaded member 52 on one ofits ends which is pivotally connected as by a pin 54 to an end of one ofthe levers 20. The other lever 20 has a bifurcated end 56 also shown inFIG. 2 pivotally connected to bosses 58, fixed to the wall 46 of thechamber. Fluid under pressure, which may be air, is communicated to thechamber through a line 60 urging the piston 42 toward the left, asillustrated in FIG. 1, to compress spring 36 and hold the brake in itsreleased position as disclosed.

To apply the brake, the air pressure is released and the spring urgesthe piston 42 toward the right. This causes movement of the member 52toward the right drawing the levers 20 toward each other until the pads14 attain frictional engagement with the opposite sides of the disc.When air pressure is applied to release the brake, the levers arecentered by adjustable limit stops 64 so that the pads 14 do not drag onthe disc when they are not performing their braking function.

One of the advantages of the present invention resides in thedisposition of the actuating chamber 38 directly between the levers 20so that, as the spring expands and moves the levers toward each other,the force applied to the pads 14 on the opposite sides of the disc isexactly the same. This is also a result of the fact that the actuatingchamber has no connection with any fixed part of the vehicle but onlywith the pivoted levers. Thus, the braking mechanism is automaticallyself-centering and this self-centering feature is accomplished throughsimple and inexpensive structure. It is also, as previously mentioned,highly desirable that the brake is spring applied so that it is notdependent upon fluid supply lines or manual force to operate underemergency conditions.

What is claimed is:

1. A vehicle brake comprising a disc which rotates when the vehicle isin motion, a pair of friction pads disposed for engagement with oppositesides of the disc, a pivoted lever supporting each pad, said levershaving spaced apart ends moveable toward each other to bring the padsinto braking contact with the disc and moveable away from each other todisengage the pads from said disc, a pair of limit stop means, one foreach lever, which act upon said levers to center said levers withrespect to said disc when said levers are moved to said disengagedposition, and actuating means disposed between and supported entirely bysaid levers.

2. The brake of claim 1 in which the actuating means comprises springmeans for applying the brake and fluid pressure means for releasing thebrake.

3. The brake means of claim 1 in which the actuating means is acylindrical chamber with a reciprocable piston therein and the springpressure is applied to one side of the piston and fluid pressure to theother side.

4. The brake means of claim 3 in which the piston is connected with onelever and the chamber is connected with the other.

1. A vehicle brake comprising a disc which rotates when the vehicle isin motion, a pair of friction pads disposed for engagement with oppositesides of the disc, a pivoted lever supporting each pad, said levershaving spaced apart ends moveable toward each other to bring the padsinto braking contact with the disc and moveable away from each other todisengage the pads from said disc, a pair of limit stop means, one foreach lever, which act upon said levers to center said levers withrespect to said disc when said levers are moved to said disengagedposition, and actuating means disposed between and supported entirely bysaid levers.
 2. The brake of claim 1 in which the actuating meanscomprises spring means for applying the brake and fluid pressure meansfor releasing the brake.
 3. The brake means of claim 1 in which theactuating means is a cylindrical chamber with a reciprocable pistontherein and the spring pressure is applied to one side of the piston andfluid pressure to the other side.
 4. The brake means of claim 3 in whichthe piston is connected with one lever and the chamber is connected withthe other.